There is a Japanese legend who talks about a method to find cats that have left the house and never come back. 

The technique is to talk to the street cats in the neighbourhood as if you would talk to anyone.  Ask them about your cat, describe it and what it is, their hair tone, even tell them the cats' name.

Ask them to help you find it, tell him how much you love him and how much you want him or her to come home.

They will communicate with each other to help your cat return home ❤